Content distribution systems are fairly common in Internet and corporate (intranet) environments. One example for the Internet is Windows Update/Microsoft Update, which is used to distribute software updates for Microsoft Windows® and other Microsoft Corporation products across the Internet.
Some of this content has a sensitive nature. For example, security updates (often in the form of patches) are generally released on the second Tuesday of each month, and once released, need to be installed quickly on as many computers as possible. This is because hackers and the like are able use the security update itself as a model to understand potential security exploits that the patch fixes, and then create code that takes advantage of the vulnerability on machines that are not yet patched. Once in possession of the security fix, the time for hackers to exploit a vulnerability may be short, such as one day or less.
As one consequence, updates are made available to as many systems as possible in as short a time as possible. However, this requires a potentially huge amount of network bandwidth, as millions of clients download the updates. This can cause adverse network congestion effects across the Internet, and also leads to huge swings in network utilization depending on the day of the month. That is, huge capacity is needed, but for only a short period of time each month. Similarly, congestion can occur in a corporate environment, in which the number of systems to update is much smaller, but the network bandwidth and associated infrastructure is much smaller as well, leading to local network congestion and/or interference with business operations.